Deuterium isotope fractionation between ortho-alkyl substituted phenols and t-butylthiol in oxygen bases

• Autorzy: Wawer A. , Jelińska-Kazimierczuk M. , Szydłowski J.
• Języki publikacji: EN

Abstrakty

EN

Equilibrium isotope effect in the exchange reaction of deuterium between phenol (P), 2-isopropylphenol (IPP), 2,6-diisopropylphenol (DIPP), 2,6-ditertbutyl phenol (DTBP) and tertbutylthiol (TBT) has been studied at 298 K. The fractionation factors (alpha) have been measured in cyclohexane and carbon tetrachloride solution and in a few oxygen bases: acetone, 1,4-dioxane, ethyl formate, ethyl ether, tetrahydrofurane, N,N-dimethylformamide, dimethylsulphoxide and hexamethylphosphoramide. Using chemical shifts of phenol OH protons, the thermodynamic parameters of complex formation with the oxygen bases have been determined. The experimental data show that ln alpha correlates with the formation enthalpy of the phenol-oxygen base complex in DIPP-TBT-base system but there is no simple correlation in IPP-TBT-base system. Futhermore it was found that in DTBT-TBT-base system ln alpha depends linearly on the basicity of the (solvent DN parameters). On the other hand, ln alpha correlates with acidic parameters of the solvents (AN) in IPP-TBT-base and P-TBT-base systems. All above correlations are explained by taking into account two competition processes: selfassociation of phenol molecules and their solvation by oxygen bases.

Słowa kluczowe

EN

isotope effects; deuterium; equilibrium; thermodynamics; association; solvation

• Wydawca: Polskie Towarzystwo Chemiczne
• Czasopismo: Polish Journal of Chemistry
• Rocznik: 1998
• Tom: Vol. 72, nr 3
• Strony: 618--626
• Opis fizyczny: Bibliogr. 18 poz., tab., wykr.

Twórcy

autor

Wawer A.

autor

Jelińska-Kazimierczuk M.

autor

Szydłowski J.

• Chemistry Department University of Warsaw Żwirki i Wigury 101 02-089 Warsaw Poland,